These results show that red and pearl photo-selective nets create optimal growing conditions for the growth of the plant and produce fruits with thicker pericarp, the highest lycopene content, a satisfactory level of taste index and can be further implemented within protected cultivation practices.

The concept of photo-selective netting was studied in a sweet pepper (Capsicum annuum L.) cultivar 'Cameleon' from summer cultivation in south Serbia (under high solar radiation 910 W m -2 , with a photosynthetic photon flux density of 1661 µmol m -2 s -1 ), under four different coloured shade-nets (pearl, red, blue and black) with 40% relative shading. The aim of the study was to determine how different environmental control technologies, coloured shade-nets as net house or plastic-house integrated with coloured shade-nets, could influence plant parameters, production and quality traits in pepper fruits. Shade-grown leaves generally have higher total chlorophyll and carotenoid content than control leaves. Pericarp fruit thickness was significantly higher in peppers grown under red net house (4637.10 µm) and black net house (4609.32 µm) compared to the open field -control (3116.19 µm). The highest concentration of total soluble solids (TSS) was detected in pepper fruits grown under the open field conditions (8.03%). Pepper fruits grown in plastic tunnels had significantly lower TSS content (6.58%). Total acid (TA) content was 0.19 in the control and 0.25 in pepper fruits grown under red nets. The highest concentration of vitamin C was detected in peppers grown in plastic tunnels integrated with red coloured nets (175.77 mg 100 g -1 ). These results show that red and pearl photo-selective nets create optimal growing conditions and increase the total fruit yield as well as the number of fruits with fewer physiological disorders and with thicker pericarp. Photoselective pearl and red nets can be recommended for sweet pepper 'Cameleon' with respect to quality and bioactive compound and can furthermore be implemented in protected cultivation practices.

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Thymus vulgaris L. (thyme), Origanum majorana L . (marjoram), and Origanum vulgare L . (oregano) were used to determine whether light modification (plants grown under nets with 40% shaded index or in un-shaded open field) could improve the quantity and quality of essential oils (EOs) and antioxidant activity. The yield of EOs of thyme, marjoram, and oregano obtained after 120 min of hydrodistillation was 2.32, 1.51, and 0.27 mL/100 g of plant material, respectively. At the same time under shading conditions plants synthetized more EOs (2.57, 1.68, and 0.32 mL/100 g of plant material). GC/MS and GC/FID analyses were applied for essential oils determinations. The main components of the thyme essential oil are thymol (8.05–9.35%); γ-terpinene (3.49–4.04%); p-cymene (2.80–3.60%) and caryophyllene oxide (1.54–2.15%). Marjoram main components were terpinene 4-ol (7.44–7.63%), γ-terpinene (2.82–2.86%) and linalool (2.04–2.65%) while oregano essential oil consisted of the following components: caryophyllene oxide (3.1–1.93%); germacrene D (1.17–2.0%) and (E)-caryophyllene (1.48–1.1%). The essential oil from thyme grown under shading (EC 50 value after 20 min of incubation) have shown the highest antioxidant activity – 0.85 mg mL −1 in comparison to marjoram and oregano (shaded plants EC 50 19.97 mg mL −1 and 7.02 mg mL −1 and unshaded, control plants EC 50 54.01 mg mL −1 and 7.45 mg mL −1 , respectively). The medicinal plants are a good source of natural antioxidants with potential application in the food and pharmaceutical industries. For production practice, it can be recommended to grow medicinal plants in shading conditions to achieve optimal quality parameters.

The present study focuses on the yield, chemical composition, and antioxidant activity of essential oils from different parts (flowers or leaves/stems) of cultivated plants grown under pearl shade nets with a 40% shaded index or in nonshaded plants and wild-grown oregano. The chemical composition of isolated essential oils was determined by GC/MS and GC/FID. Antioxidant activity was determined using the DPPH assay. The highest yield of oregano essential oils (OEOs) was obtained in cultivated shaded plants (flowers) at 0.35 mL/100 g p.m., in contrast to nonshaded plants (flowers), where the yield of OEOs was low (0.21 mL/100 g p.m.). Qualitative and quantitative analyses of the OEOs identified 16–52 constituents that varied with origin and plant organs. The oxygenated sesquiterpene caryophylleneoxide (7.4–49.9%) was predominant in all the essential oil samples. Other major constituents were sesquiterpene hydrocarbon-germacrene D (8.4–22.5%) and (E)-caryophyllene (8.5–10.8%), monoterpene hydrocarbon-sabinene (1.6–7.7%), and oxygen-containing monoterpenes-terpinen-4-ol (1.5–7.0%). The plant part has a significant effect on the antioxidant activity of OEOs, while the influenceof modified light under the shade nets is significantly lower. The OEOs from wild flowers showed the highest antioxidant activity, with an EC50 value of 4.78 mg/mL. OEOs from cultivated nonshaded plants (flowers) recorded the lowest antioxidant activity with an EC50 value of 24.63 mg/mL. The results suggest that the yield and quality of OEOs can be scaled-up by optimizing plant production in comparison with wild-growing plants. The content and quality of OEO can be increased by optimizing its production compared to plants from the spontaneous flora. Adequate cultivation techniques, such as shading, can achieve high-quality oregano yields and better quality parameters in terms of specific OEO components and meet the different requirements of the market and industrial sectors.

The aim of this study was to determine the antimicrobial activity of essential oils obtained from sweet basil (Ocimum basilicum L. cv. ‘Genovese’) cultivated in the open field under different shading conditions (red, blue, and pearl nets with a shade index of 50% and full sunlight exposure (control plants)), harvested at different times. The antimicrobial activity of basil essential oils (BEOs) obtained from all samples was determined for four microorganisms, while determinations for an additional five microorganisms included samples from non-shaded plants, plants grown under red and pearl nets, and second harvest of plants grown under blue net. Basil essential oil exhibited antimicrobial activity surpassing the activity of relevant commercial antibiotics regardless of growing conditions in the case of B. cereus, K. pneumoniae and C. albicans, while superior antimicrobial activity was exhibited in the case of essential oils from plants grown under blue nets in the case of S. aureus, E. coli and P. vulgaris. The influence of the application of colored shading nets was highly significant (p < 0.01) in the cases of all analyzed microorganisms except C. albicans and P. aeruginosa, while the influence of harvest time was proven in the cases of all microorganisms except K. pneumoniae. ANOVA proved that antimicrobial activities are highly dependent on the methods of plant production, shading treatment, and harvest time. Obtained results are discussed in relation to previously determined composition and yield of essential oils from basil grown under shade nets and harvested in different periods.

Summary The photoselective, light-dispersive shade nets can be used as an alternative to protect crops from adverse environmental conditions such as; excessive solar radiation, heat and drought stress, wind and hail, birds, flying pests, thus improving crop’s production, yield and quality. The physiological parameters discussed in the review include: vegetable growth parameters (leaf area, leaf chlorophyll), tissue structure, fruit ripening, physiological disorders, pest and disease incidence, fruit quality parameters (soluble solids content and titratable acidity), bioactive compounds (antioxidant activity, ascorbic acid, carotenoid and flavonoid contents) and aroma volatile compounds at harvest. Also, it is evident in the reviewed literature that light quality influences the biosynthesis, accumulation and retention of vegetable phytochemicals, as well as the decay development during storage. These new strategies to modulate light quality should be conveyed to vegetable producing farmers, thus allowing them to preserve the freshness and post-harvest quality of vegetables for an extended period of time, and to meet the consumers demand for vegetables with high nutritional value all year round. Research on light manipulation in horticultural systems is necessary for a sustainable and market-oriented open field and greenhouse vegetable production in the future.

The purpose of this study was to examine differences between postharvest treatments, either washed (hot water, H 2 O 2 and Na 2 OCl) or non-washed (control) carrot roots and the effect of different storage conditions, S 1 (0°C and > 95% RH) or S 2 (0-2°C and < 90% RH) on the compositional changes. Losses of mass, β-carotene and vitamin C in carrot taproot (Daucus carota L. cv.'Maestro F 1 ') were monitored during 160 days of cold storage (in both cold room) plus 20 days at 20°C (market simulation). At the end of 180 days of storage the percentage mass loss ranged from 3.1 to 33.2% depending on the storage condition and disinfection treatment. Loss of β-carotene during storage was higher in the S 2 (28.2-46.9%) than in the S 1 cold storage (7.8-20.7%). The vitamin C loss in carrot root inside the S 1 cold room ranged from 2.0% to 18.2%, while the vitamin C loss was significantly higher (20.7%-52.3%) under simple refrigerated cold storage (S 2 ). Our experimental results indicate that prestorage root washing (Na 2 OCl) significantly reduced weight loss, while hot water treatment maintaining a quality (β-carotene and vitamin C). Storage at cold room (S 1 ) after these treatments, is a practical strategy for reducing weight loss, β-carotene and vitamin C contents in the carrot during prolonged storage.